PURPOSE: To make stable the coupling state between an ear plug and an ear shell, by extending the ear plug to a direction with a slope to the oscillating direction of a diaphragm plate.

CONSTITUTION: A diaphragm plate 1 is oscillated based on an electric signal coupled to a coil 11. The amplitude of the oscillation is controlled with an air layer of a gap 4 to produce a sound wave and the sound wave is discharged externally from a sound way 6 of an ear plug 5 via air gap 18. Thus, the ear plug 5 is adhered to the inlet of the external ear shell by only falling a converter 3 in the external ear shell, allowing to load the earphone stably.